QuickBooks Desktop 2026 multi-user mode breaks after Windows security updates, throwing error 6010, -100 when the Database Server Manager loses its network connection. The error:

QuickBooks has encountered a problem and needs to close. We are sorry for the inconvenience. Error: 6010, -100.

Quick Fix

Restart the QuickBooks database service, then reopen the company file.

  1. Press Win + R, type services.msc, press Enter.
  2. Find QuickBooksDB36 in the list.
  3. Right-click and select Restart.
  4. Open QuickBooks and try connecting to the company file.

If that alone fixes it, set the service to auto-recover on failure (see Step 1 below) so the next Windows update does not take you down again.

What Causes This

DCOM security hardening and RPC protocol changes in Windows updates cause the QuickBooks Database Server Manager service (QBDBMgrN) to drop its network connection to the host. When the host cannot manage multi-user access, every workstation trying to open a shared company file hits 6010, -100. The pattern is the same as fix printer error 0x0000011b . Microsoft tightened RPC rules, older services fall over.

Full Fix Steps

Step 1: Configure QBDBMgrN Auto-Recovery

Keep the service running even when Windows updates reset it.

  1. Open services.msc.
  2. Double-click QuickBooksDB36 and go to the Recovery tab.
  3. Set First failure, Second failure, and Subsequent failures to Restart the Service.
  4. Click Apply and OK.

Step 2: Open Firewall Ports

DCOM changes may block QuickBooks ports. Run this in an elevated PowerShell prompt:

New-NetFirewallRule -DisplayName 'QB 2026 Inbound' -Direction Inbound -Protocol TCP -LocalPort 8019,55383,55384,55385,55386,55387 -Action Allow
New-NetFirewallRule -DisplayName 'QB 2026 Outbound' -Direction Outbound -Protocol TCP -LocalPort 8019,55383,55384,55385,55386,55387 -Action Allow

Restart QuickBooks after applying the rules.

Step 3: Rename .ND and .TLG Files

Corrupt network descriptor files block the host from seeing the company file. Renaming them forces QuickBooks to rebuild them clean.

  1. Browse to the folder containing your company file.
  2. Find the files with .ND and .TLG extensions that match your company file name.
  3. Rename each: add .old to the end so they become companyfile.qbw.nd.old and companyfile.qbw.tlg.old.
  4. Open QuickBooks. It will create fresh versions automatically.

Step 4: Check Registry Install Path

Windows updates sometimes reset the QuickBooks installation path in the registry, which points the database manager at the wrong folder.

  1. Press Win + R, type regedit, press Enter.
  2. Navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Intuit\QuickBooks\26.0
  3. Find the InstallDir value.
  4. Confirm the path reads: C:\Program Files (x86)\Intuit\QuickBooks 2026
  5. If wrong, right-click InstallDir, select Modify, and enter the correct path.

Need help with QuickBooks errors on your network? Contact Rain City Techworks.